1. Field of the Invention
This invention relates to the field of systems for applying glue, and more particularly to an in-plate hot glue application system for folding machines, which in-plate hot glue application system can be quickly fitted onto any number of folding racks for folding machines and easily adjusted to accommodate a desired hot glue application, even for relatively short folding and glue runs.
2. Description of the Prior Art
A tremendous volume of printed material is generated and distributed around the world. Much of this printed material comprises sheet material such as printed paper which is folded and which can also be detachably retained in a closed position so that it may be mailed and otherwise handled without inadvertently opening up. For small folding jobs, or for very complicated folding projects, hand folding is often employed. For large volume runs of folded materials, folding machines are used when practical.
These folding machines include folding plates or buckle plates, wherein each buckle plate is used to create a single fold in a sheet of material. For example, tri-fold materials are folded using folding machines with two racks. There are several means to retain folded material in a closed position. These means include use of staples, paper and plastic stickers, tear strips, and adhesives, just to name a few. Quick release adhesives have gained popularity for use in detachably holding together folded printed material in a closed position.
These quick release adhesives typically comprise hot melt glues which are applied in a heated form and which cool quickly, yet retain elasticity. In their best form, once applied, these hot melt adhesives hold the folded material together well, yet allow the folded pages to be easily peeled apart without damaging the printed material. These hot melt adhesives typically are clear or transparent.
The hot glue applicators typically use either an electric or pneumatic applicator, which dispenses the desired quantity of hot glue to the material to be adhered together. Manufacturers of such hot glue dispensers include Robatech, of Switzerland, and the Slautterback Corporation of Monterey, California, among others.
Generally, after the printed material is folded, the folded printed material is sent to a different machine to apply the hot melt adhesive. However, it is desirable to simplify the manufacturing process (by eliminating steps) and minimize the need for expensive equipment to the greatest extent possible. The inventor herein is familiar with in-plate gluing systems in which electric adhesive applicators are fixed to a moveable sheet stop of a buckle plate. In such in-plate gluing system, however, since the adhesive applicators are fixed in position to the movable sheet stop of the buckle plate, the position of the adhesive applicators relative to the front of the movable sheet stop and the side to side position of the adhesive applicators within the rack is also not readily adjustable once positioned.
Since there is no simple means to provide for adjustability of the adhesive applicators on buckle plates of such in-plate gluing system, it is relatively time consuming to set up buckle plates with adhesive applicators. As a result, buckle plates tend to become set up and dedicated for particular runs. Another issue is cost. Adhesive applicators, the photoelectric eyes used therewith, and the various heated glue hoses and other parts are relatively costly. It would therefore be desirable to have an in-plate gluing system that can be set up easily and quickly, and which can be swapped out to other buckle plates to obviate the need to purchase separate in-plate gluing systems for the sets of buckle plates for each fold and glue job.